Open surgical division of the tight lateral retinaculum on the outer side of the knee to correct patellar maltracking or instability.

Verified May 8, 2026 · 6 sources ↓

Medicare: $442.90
Total RVUs: 13.26
Global, days: 90
Region: Knee

Drawn from AAPCKzanowCMSGomedicalbillingMdclarity

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

Specify the surgical approach as 'open' — arthroscopic releases are coded differently and operative notes that omit approach type are audit targets.
Document the clinical indication by name: patellar subluxation, lateral patellar compression syndrome, or maltracking with failed conservative treatment.
Record the extent of retinacular release — partial vs. complete division — and any intraoperative findings about patellar tracking before and after release.
If performed with another knee procedure (e.g., 27420), document medical necessity for each service independently, noting that the retinacular release is integral to patellar reconstruction and should not be separately billed.
Include laterality (left or right knee) in the operative note and on the claim — required for correct modifier application (LT/RT).

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 24 Unrelated E/M during global 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 58 Staged or related 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27425 covers an open lateral retinacular release — a procedure in which the surgeon directly incises the fibrous lateral retinaculum to reduce excessive lateral pull on the patella. The primary indications are patellar subluxation, chronic lateral patellar compression syndrome, and maltracking that hasn't responded to conservative care. 'Open' is the operative word: the arthroscopic equivalent is coded separately, and using 27425 for a scope-assisted release is a mismatch that invites downcoding or denial.

The 90-day global period is the dominant billing constraint for this code. All routine post-op visits, dressing changes, and rehabilitation management related to the release are bundled through day 90. Unrelated E/M services in that window require modifier 24; a decision for a staged or new surgical procedure requires modifier 79.

The most critical NCCI bundling issue: 27425 is inclusive to 27420 (patellar dislocation reconstruction). If your surgeon performs both in the same session, you bill 27420 only — modifier 59 on 27425 does not override this edit and represents incorrect coding per AAOS Global Service Data guidance.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	5.26
Practice expense RVU	6.89
Malpractice RVU	1.11
Total RVU	13.26
Medicare national rate	$442.90
Global period	90 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$442.90
HOPD (APC 5113) Hospital outpatient department	$3,342.87
ASC (PI A2) Ambulatory surgical center (freestanding)	$1,644.87

Common denial reasons

The recurring reasons claims for CPT 27425 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Bundling with 27420: lateral retinacular release is inclusive to patellar dislocation reconstruction per NCCI edits; billing both results in automatic denial of 27425.
Approach mismatch: billing 27425 when the operative note describes an arthroscopic or mini-open technique — payers audit operative notes and will downcode or deny.
Missing laterality modifier when payer requires LT or RT on unilateral knee procedures.
Post-op E/M visits billed without modifier 24 during the 90-day global period are denied as already bundled into the procedure payment.
Unsupported medical necessity: claims lacking documented failed conservative treatment or a specific diagnosis (patellar instability, subluxation) are denied for insufficient clinical justification.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01Can I bill 27425 alongside 27420 for patellar reconstruction in the same session?

No. Lateral retinacular release is inclusive to 27420 per AAOS Global Service Data and NCCI edits. Appending modifier 59 to 27425 does not override this bundle and constitutes incorrect coding — bill 27420 only.

02What's the difference between 27425 and the arthroscopic lateral retinacular release?

27425 is strictly the open approach. Arthroscopic lateral retinacular release is reported with 29873. Using 27425 for a scope-assisted procedure is a code-approach mismatch that payers flag on post-payment audit.

03Does 27425 carry a global period, and what does that mean for post-op visits?

Yes — 90-day global. Routine post-op E/M visits related to the release are bundled through day 90. Append modifier 24 for unrelated E/M visits and modifier 79 for unrelated surgical procedures performed during that window.

04When is modifier 22 appropriate for 27425?

Modifier 22 applies when the procedure is substantially more complex than typical — for example, severe adhesions, prior surgical scarring, or morbid obesity that significantly extends operative time. Document the added complexity explicitly in the operative note; payers require chart-level justification before increasing payment.

05Is 27425 ever billed bilaterally, and how should that be reported?

Bilateral open lateral retinacular release in a single session is rare but codeable. Report 27425 with modifier 50 for bilateral, or with LT and RT on separate lines per payer preference. Verify individual payer rules — some require 50, others require two line items.

06What ICD-10 diagnoses best support 27425?

The strongest supporting diagnoses are patellar subluxation (M22.1x), lateral patellar compression syndrome (M22.2x), and recurrent dislocation of the patella (M22.0x). Document the specific laterality suffix — payers flag claims where the diagnosis laterality doesn't match the procedure modifier.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures the approach (open vs. arthroscopic), the specific lateral retinacular structure released, intraoperative patellar tracking assessment pre- and post-release, and the primary diagnosis driving surgery. It also flags when 27420 is dictated in the same session — prompting the biller that 27425 is bundled and should not be separately reported, preventing an NCCI-edit denial before the claim is submitted.

See how Mira captures CPT 27425 documentation